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United States Patent | 5,115,811 |
Hartlaub ,   et al. | May 26, 1992 |
A fiber-optic sensor for measuring a parameter of a test fluid, including a chemical sensor, incorporating a dye composition which displays changes in its optical properties correlated to changes in the parameter to be measured. The sensor is coupled to an apparatus including a light source, and means for measuring light received from said sensor at three different peak wavelengths. The first wavelength is chosen such that the optical characteristics of the dye with respect to that wavelength do not change significantly with changes in the parameter to be measured. The second and third wavelengths are chosen such that optical characteristics of the dye with respect to these wavelengths do change along with changes in the parameter to be measured, and also change as a function of temperature. The light received from the sensor at first, second and third wavelengths is compared to determine the temperature of the test fluid and to provide a temperature correction for the parameter to be measured.
Inventors: | Hartlaub; Jerome T. (New Brighton, MN); Schweitzer; Jeffrey A. (St. Paul, MN); Seifert; George P. (Shoreview, MN) |
Assignee: | Medtronic, Inc. (Minneapolis, MN) |
Appl. No.: | 516621 |
Filed: | April 30, 1990 |
Current U.S. Class: | 600/342; 356/39; 600/359; 600/361 |
Intern'l Class: | H61B 005/14 |
Field of Search: | 128/634,636,637,736 374/17-19,141 250/227.14,227.18,226 356/412,39-41 |
4200110 | Apr., 1980 | Peterson et al. | |
4362645 | Dec., 1982 | Hof et al. | 374/160. |
4476870 | Oct., 1984 | Peterson et al. | 128/634. |
4551022 | Nov., 1985 | Tagaya | 250/226. |
4560286 | Dec., 1985 | Wickersheim | 128/736. |
4710623 | Dec., 1987 | Lipson et al. | 128/634. |
4785814 | Nov., 1988 | Kane | 128/634. |
4842783 | Jun., 1989 | Blaylock | 128/634. |
4895156 | Jan., 1990 | Schulze | 128/634. |
"Fiber-Optic Sensors for Biomedical Applications" by Peterson and Vurek, published in Science, Apr. 13, 1984, pp. 123 through 127. "A New Non-Perturbing Temperature Probe Using Semiconductor Band Edge Shirt", published in Journal of Bioengineering, vol. 1, pp. 541 through 545, 1977. "Thermometry and Dosimetry of Heat with Specific Reference to the Liquid-Crystal Optic Fiber Temperature Probe" by Livingston, published in Radiation and Environmental Biophysics, vol. 17, pp. 223 through 243, 1980. "Optical-Fibre Thermometer for Medical Use" by Scheggi et al., published in IEE Proceedings, vol. 131, Pt.H, No. 4, Aug. 1984. |